Orthoclase , Tosudite Locality: Schori, Wallis, Switzerland Size: thumbnail, 3 x 2.5 x 2.2 cm Adularia w/Chlorite Very sharp interpenetrating twinned crystals that are gemmy and have an attractive coating of Chlorite on most of the surfaces. Even so, the luster on this superb thumb is excellent. 3 x 2.5 x 2.2 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Tosudite
Tosudite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₀.₅(Al,Mg)₆(Si,Al)₈O₁₈(OH)₁₂·5H₂O.
It is a member of the Corrensite, Clay structural group.
Key properties: Mohs hardness 1; specific gravity 2.83; Nonmetallic luster; optically biaxial.
IMA symbol Tos, grandfathered status — known before the IMA’s founding, named in 1963.
A hydrothermal alteration product of intermediate to felsic igneous rocks. From the alteration of sandstone by acidic pore waters.
It is found associated with Rectorite, dickite, quartz, fluorite (Tooho mine, Japan).
The mineral was named to honor Professor Toshio Sudo (1911{), mineralogist and crystallographer, of the University of Tokyo, Tokyo, Japan.